The present invention relates to a process for applying discrete web portions, such as tapes or tape attachment zones or elastic bands, on to a receiving web, such as a diaper. In particular the process is applicable to high speed production lines used in the manufacture of diapers and similar products.
Diapers, adult incontinence products and the like, are usually manufactured on high speed production machines. Such machines generally form a continuous web which is transported through the machine in the machine direction in order to pass through a series of work stations. At each work station an operation is carried out. One common operation is to attach features such as tapes or tape attachment zones or elastic bands, on to a receiving web. Such features are often required to be discrete xe2x80x9cpatchesxe2x80x9d, rather than continuous features which lie along the whole length (in the machine direction) of the receiving web. Such patches may be applied by various known techniques, including the technique known as xe2x80x9ccut and slipxe2x80x9d.
An example of a known process is to provide an apparatus which receives discrete parts traveling at a first speed and applies them to a receiving web traveling at a second (usually faster) speed.
U.S. Pat. No. 5,660,657, issued on Aug. 26, 1997, illustrates an apparatus of this type in FIGS. 32 and 33. In the illustrated apparatus a rotating transfer assembly receives and holds the discrete parts, and transfers them to the receiving web.
Furthermore this patent discloses an apparatus which receives a continuous web traveling at a first speed, the web being cut into discrete parts and then applied to a receiving web traveling at a second (usually faster) speed. The end product has discrete parts which are spaced uniformly along the receiving web. FIGS. 35 and 36 of U.S. Pat. No. 5,660,657 illustrate such an apparatus. In the illustrated apparatus three rotating transfer assemblies receive and hold the discrete parts and transfer them to the receiving web. Each transfer assembly is mounted on an independently rotating shaft having a variable angular velocity.
Hence it is known to have a process with the steps of: feeding a web into a web transfer apparatus at a first speed; cutting a web portion off the web; and accelerating the web to the speed of a receiving web. This prior art process results is a receiving web upon which discrete parts are uniformly spaced.
However, in some cases, it would be advantageous to provide a receiving web upon which discrete parts are unevenly spaced. For example the spacing between a first and second, adjacent, discrete parts might be a distance X, whist the spacing between the second and third, adjacent, discrete parts might be a distance Y. Subsequently, the spacing between the third and fourth, adjacent, discrete parts might be the distance X again; the spacing between the fourth and fifth, adjacent, discrete parts might be Y again, and so on.
Furthermore, in some cases, it would be advantageous to provide discrete parts on to a receiving web whereby adjacent discrete parts are of unequal length (length being measured in the machine direction).
The object of the present invention is to provide a process which would provide a receiving web upon which discrete parts are either unevenly spaced, or which are unequal in length, or both, and which could be easily adjusted to provide different spacings between the discrete parts, and/or different lengths of discrete parts, so that different products, or different sizes of products, can easily be manufactured on the same apparatus.
This object is achieved by: separating the web portion into at least a first web portion and a second web portion by means of at least a second cut; moving the web portions relative to each other so that they are spaced apart; and applying each of the spaced apart web portions to the receiving web.